Zuckerberg has a different view. On Sunday, he responded to a question about Musk's warnings by saying he was tired of the fear-mongering.

"With AI especially, I'm really optimistic," Zuckerberg said during a Facebook Live broadcast. "I think that people who are naysayers and kind of try to drum up these doomsday scenarios -- I just, I don't understand it. I think it's really negative and in some ways I actually think it is pretty irresponsible."

Musk shot back on Tuesday morning with a tweet saying, "I've talked to Mark about this. His understanding of the subject is limited."

I've talked to Mark about this. His understanding of the subject is limited.

Musk, who's already leading space exploration projects and major tunneling initiatives, is now trying to develop AI that he hopes will have a positive impact on humanity. He's heading up a startup called Neuralink that intends to build devices to connect the human brain with computers.

In his Facebook Live broadcast on Sunday, Zuckerberg said that AI could be a force for good because it helps power self-driving cars and diagnose illnesses.

"If you're arguing against AI, then you're arguing against safer cars that aren't going to have accidents. And you're arguing against being able to better diagnose people when they're sick. I just don't see how, in good conscience, some people can do that. I'm just much more optimistic on this, in general, than probably a lot of folks are," Zuckerberg said.

Facebook and Tesla did not immediately respond to requests for comment on the feud.